Consider the following general model specification: 𝑌 = 𝑓 ( 𝑋 1 , 𝑋 2 , 𝑋 3 𝑋 4 , 𝑋 5 , 𝑋 6 , 𝑋 7 , 𝑋 8 ) . Where the 9 variables are: Y = Test score of the mid-term exam X1 = Time spent studying for the exam X2 = Degree of course difficulty (measured by an index #) X3 = Class size (number of students) X4 = Experience/knowledge of the teacher   X5 = Student’s college experience (college credits previously earned) X6 = Quantity of the student’s outside (non-academic) activities X7 = Level of the student’s determination to succeed (measured by an index #) X8 = Dummy (=1 if the course is face-to-face; 0 otherwise (online)) For each of the 2 cases of omitted variables below, determine the sign (positive/negative) of the bias – you must complete columns 3, 4, and 5 in the table below.  Case OM IN 𝛽 𝑂 𝑀 𝛼 1 − ℎ 𝑎 𝑡 BIAS 1 X5 X6 Sign is [ Select ] negative positive Sign is [ Select ] negative positive Bias is [ Select ] negative positive 2 X4 X1 Sign is [ Select ] negative positive Sign is [ Select ] negative positive Bias is [ Select ] negative positive